1) Linguistics thesauri
Exercise: Search for the words: football, spring, although.
Which system has a better interface? Which search options are
available? What happens if you misspell a word? What are
the broader terms for "football"? Can you find antonyms of "spring"?
- group words by synonyms
- arrange words in a hierarchy that represents the word meanings
2) Information retrieval thesauri
Establish formal relationships among terms, such as
- BT/NT for broader term/narrower term (hierarchy)
- USE/UF (UF means "use for") for synonyms
- RT for other related terms
Exercise: Find documents on informatics and thesaurus.
In what way does the thesaurus on the right side help with the search?
Can you use it to broaden or narrow a search?
Instructions: Type "football" into the textbox and click "Look up".
In the thesaurus that appears on the right side select terms
(either "football" or its broader terms or both). Then click
"Add to Set1". Then click on the left side on "search". It will then
show documents about "football".
3) Lexical databases: WordNet
Establishes semantic relations among words:
a) Search for spring, football, although, informatics in the four
- hyponymy/hypernymy (hierarchy)
- meronymy (part-whole relations)
- antonymy (opposites)
b) Try the different search options in WordNet.
Can you find meronyms and antonyms for spring? How many senses
c) In the Plumb Design Thesaurus, can you establish
a connection between spring and fall?
d) Try the different search
options in Lexical FreeNet. Can you find a connection between
spring and fall in Lexical FreeNet? Try the search for
famous people in Lexical FreeNet.
4) Formal Ontologies: CYC and Ontolingua
Exercises: a) In CYC: have a look at Food and Clothing.
What kinds of food are mentioned? How is food prepared and consumed?
What are the other main concepts related to food? What types of clothes
does CYC know of? What are the main activities related to clothes?
- establish concepts and relationships in a formal manner
- to be used by computers (software agents), not for human end-users
b) In Ontolingua: click on "documents". Have a look at the class hierarchy,
the relations and function. (Ignore the incomprehensible stuff at the
top of the page.)